I had a strange split week after Easter. I went to Yale University, as the guest of the Elizabethan Club, to deliver the paper, Is British Theatre As Good As It Claims? My answer was broadly affirmative, not least because of its capacity to engage with the public world. I then dashed from Yale to the University of Leeds to attend a three-day conference on Harold Pinter. My argument about our theatre's political vibrancy was confirmed by a staggering collage from the Belarus Free Theatre called Being Harold Pinter, which Alfred Hickling has eloquently reviewed.

In Britain one question is constantly asked about Pinter: are his late, overtly political plays as rich and fascinating as earlier, acknowledged masterpieces like The Caretaker and The Homecoming? In the end, it's a parochial question. The more you travel, the more you realise the universal resonance of Pinter's studies of political oppression. I've never forgotten seeing One for the Road in Barcelona, where an audience that had collective memories of Franco-ist fascism responded to this study of state cruelty with an intensity I've never witnessed in Britain.

But something extraordinary happened in Leeds. The Belarusian actors presented a 90-minute show in which Pinter's Nobel acceptance speech cued in compressed versions of his late political plays. Artistically, big risks were taken. Nicolas in One for the Road was played by a woman who brandished a flaming torch over a male victim's naked body. In Mountain Language an actor assumed the posture of a vicious guard dog. At one point the company all appeared trapped inside a polythene sheet as if gasping for the oxygen of freedom. In short, the actors turned Pinter's plays into an expression of life in Belarus: a so-called "democratic republic" that silences debate and has more policemen per head than anywhere else in the world.

What was moving was to hear the actors talk afterwards of their own struggles. They had mostly been outlawed from appearing in state-run theatres. Their own performances often took place in private houses. Several of the company had been in prison; yet there was no self-pity in their descriptions. They were simply determined artists who wanted to work and who clearly found in Pinter's plays an echo of their own experience.

This doesn't mean that Pinter's late political plays have no relevance to Britain itself: works like One for the Road, Mountain Language and Ashes to Ashes are about the global danger of diminution of freedom and loss of liberty. But, watching the brave and brilliant actors from Belarus, I was reminded of how isolated we are in Britain. We fuss about nice aesthetic distinctions. One distinguished speaker, actually American, said in Leeds that Pinter's late political plays are "timely" rather than "timeless". But I wonder. As long as there is injustice, cruelty and oppression, I believe Pinter's later works will not merely survive. They will possibly even outlast the linguistic virtuosity of some of the early plays. That, for me, was the priceless lesson of Leeds: that politics gives drama a purchase on posterity.